The present invention relates to an anti-loose screw and a die device for forming the anti-loose screw and, more particularly, to an anti-loose screw including a thread angle larger than 60° for providing an anti-loose effect when engaged with an internal thread formed in an object and having a thread angle of 60°. The present invention also relates to a combination including the anti-loose screw and the object and relates to a die device for forming the anti-loose screw.
Screws are widely used in daily life and are engaged in internal threads in objects. A C-shaped spring washer is often mounted around a screw to prevent the screw from becoming loosened from the internal thread in an object. The spring washer is compressed and deformed to provide a reactive force by its elasticity, providing an anti-loose effect. However, the spring washer can not be used in a limited space. To solve this limitation, some manufacturers apply a coating on the thread of the screw or the internal thread of the object. The coating is compressed and deformed to provide the desired anti-loose effect. However, the coating results in a significant increase in the manufacturing costs.
Thus, a need exists for a novel anti-loose screw free of coating and for a novel die device for forming the anti-loose screw.